Challenged by reporters, who noted that the unnamed student had boasted that he "could have done much better" than Cho Seung-hui, the Virginia Tech senior who shot 32 people dead in Blacksburg, Va., Naso responded.

'What is critical to remember is that nothing happened at Clackamas High School,' he said. 'The only thing that happened was some students reported to our administrator some threatening comments made by a fellow student.'

According to police, the student told classmates he would have placed bombs in the Clackamas High cafeteria and set them off during the lunch period. Investigators say they found a list of bomb-making ingredients when they searched the student at school and later found what they said were bomb-making materials at his home.

Sheriff's deputies said they destroyed explosive ingredients, fireworks and tennis balls in the boy's backyard. Deputies said other students heard the boy bragging about throwing tennis balls filled with explosives at passing cars in Happy valley last week.

When questioned by investigators about his alleged statements about blowing up the Clackamas High cafeteria, the student said he was joking, police said.

'You can't go around talking about wreaking havoc,' said Naso. 'This is a world of free speech that has limits to it.'

The student was taken to the Clackamas County Juvenile Intake Center in Oregon City and is being charged with threat of harm and unlawful manufacturing of a destructive device.

The incident is the latest in a string of school scares in the area following the Virginia Tech shootings.

A Lewis and Clark College student was detained by school authorities Wednesday morning after he was spotted wearing a decorative belt made of spent ammunition. School administrators were prepared to lock down the campus before locating the man and determining that the belt was harmless.

On the same day, a 15-year-old sophomore at Willamette High School in Eugene was arrested after a bomb exploded in a trash can near a set of school lockers there. No one was hurt in the explosion, and there was no damage done to the building. The student was charged with manufacturing a destructive device, possession of a destructive device in a public building, reckless endangerment and disorderly conduct.

'We're in a different world now,' Naso said. 'What's different about this week from four weeks ago is that you wouldn't have had students who were quite so sensitive. The behaviors themselves would have been no more acceptable four weeks ago than it is today.'

According to Naso, the school had held an assembly to highlight security concerns earlier in the week, which he believes may have prompted the students to come forward regarding their classmate's remarks.

'We considered this a serious situation,' he said. 'Any time a youngster is talking about something that could result in ultimate harm in a community, this is something we take seriously.

'These aren't pranks anymore. Our teenagers need to understand that this is no longer acceptable or tolerable in our society any more.'

In a statement, Clackamas County Sheriff's Office officials said they have a "zero tolerance" policy for verbal threats and threatening conduct.